The present disclosure relates generally to equipment utilized and operations performed in conjunction with a subterranean well and, in an embodiment described herein, more particularly provides for plugging a side pocket mandrel using a swelling plug.
A gas lift mandrel is a type of side pocket mandrel used in gas lift operations. Gas is flowed through a gas lift valve in the side pocket to thereby reduce the effective density of produced fluid (usually hydrocarbon fluid) and enhance its flow to the surface. Other uses for side pocket mandrels include chemical injection, for example, to retard hydrate formation and/or corrosion of a production tubing string, etc.
Such side pocket mandrels typically include one or more ports for permitting fluid transfer between an interior and exterior of the mandrel. For example, in a mandrel intended for gas lift operations, the ports may permit fluid flow between the interior of a tubing string in which the mandrel is interconnected and an annulus between the tubing string and a surrounding wellbore. In a mandrel intended for chemical injection operations, the ports may permit fluid flow between the interior of the tubing string and a chemical injection line which extends to a chemical source at a remote location.
Unfortunately, side pocket mandrels can sometimes become damaged or otherwise unusable or not needed. For example, one or more of the ports may become flow cut, rendering the mandrel unusable.
In the past, these problems have been resolved by installing a “dummy” valve in the side pocket to plug the ports. Such dummy valves are typically mechanically actuated to extend seals thereon and engage latches with profiles in the side pockets.
However, these sealing and latching mechanisms are not completely reliable, and the seals can be cut or otherwise damaged during the installation process. Therefore, it may be seen that improvements are needed in the art of plugging side pockets in mandrels.